<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        .row {
            /* width: 100%; */
            height: 200px;
            background-color: green;
        }
        
        .col {
            box-sizing: border-box;
            display: inline-block;
            width: 50%;
            height: 100px;
            background-color: yellow;
            padding: 0 10px;
        }
        
        .col:last-child {
            background-color: red;
        }
    </style>
</head>

<body>
    <div class="row">
        <div class="col"></div>
        <div class="col"></div>
    </div>
</body>

</html>